Why Is It Taking 20 Minutes to Mine This Bitcoin Block? • Hacker News Board

Re: Why Is It Taking 20 Minutes to Mine This Bitcoin Block?

#111

Post by mkirklions » Tue, Feb 27, 2018, 2:20 PM UTC

gowld wrote: post #81

meuk wrote: post #74

I have been thinking about this as well, in another context. When I am at the tennis court, I always seem to be surrounded by players which are far above average. This seems paradoxical, but you're more likely to meet the players which train most often, and they are also most likely to be the best tennis players.

It's also the reason why most people are less popular than their average friend is, even though they are (on average) as popular as the average person! Since popular people are on everyone's friend list, but unpopular people are only on a few friend lists, your friend list is biased toward popular people. Mathematical explanation of why Facebook makes you depressed.

As someone that has more friends('popular'), its all a matter of effort.

I go out every weekend, I talk to everyone, I ask everyone for follow up contact info.

Yeah I get turned down probably 50% of the time, but its a numbers game. Sometimes you meet incredible people, but its taking that first step that matters.

Anyway, if you want to meet people, always go to events you are invited to, meet people. No one remembers how a conversation starts, people that are weird about communication are forgettable.

Re: Why Is It Taking 20 Minutes to Mine This Bitcoin Block?

#112

Post by lawlessone » Tue, Feb 27, 2018, 3:43 PM UTC

zaroth wrote: post #3

CyrusL wrote: post #2

"Assume a hashrate and difficulty corresponding to 1 block per 10 minutes. If I uniformly randomly pick a point in time, what is the expected time between the previous block and the next block?" https://twitter.com/pwuille/status/967878361782652928

This is like a common core math problem. Poorly worded to the point of obscuring any real math talent that could be applied in finding a “correct” result, and instead we get to debate what the question means . A more interesting question, I think, is given a POW algorithm which adjusts difficultly to target a 10 minute block rate, and assuming network hash rate is constant and propagation is instant, what percentage…

What is the issue people have with Common core? seems to be just ideological.

Re: Why Is It Taking 20 Minutes to Mine This Bitcoin Block?

#113

Post by dmitriid » Tue, Feb 27, 2018, 4:12 PM UTC

bkor wrote: post #88

modeless wrote: post #79

Earlier quoted context omitted.

Yes, it takes 10 minutes on average for a transaction to be included in a block. Potentially much longer if you are unlucky or didn't pay a high enough fee. On top of that most places won't accept just one block. The standard is 6 blocks, so 1 hour on average. That's the price you pay for a truly trustless distributed system. Still (much) faster than ACH or wire transfers or securities trade settlement.

SEPA instant will settle transactions 10 seconds. Drawbacks: banks can opt to participate, initially limited to 15k EUR, plus not obvious what the cost is. Banks are charged 1 EUR per transaction, so it'll be at least 1 EUR charged to customers. The price of a transaction is as important as the speed, IMO.

Swish in Sweden [1]

Private transfers: instant transactions between individuals, no transaction fees. (Though I suspect internally they do the usual reconciliation between banks at the end of the day).

Business: instant transactions to your account from your customers. Yearly fee: 500 SEK ($61), price per transaction: 2 SEK ($0.24), price per reimbursed transaction: 2 SEK ($0.24)

There are also limits on how much money you can send in one go, but it's usually more than enough for individual transactions and for small businesses.

[1] https://www.getswish.se, https://medium.com/@etiennebr/swish-the-secret-swedish-finte...

Re: Why Is It Taking 20 Minutes to Mine This Bitcoin Block?

#114

Post by just_one_time_ » Tue, Feb 27, 2018, 4:39 PM UTC

This is a problem introduced into only the forked version of Bitcoin, Bitcoin Core/SegWit controlled by the company Blockstream, the original Bitcoin, and now Bitcoin Cash, do not suffer this problem as 0-confirmation transactions were not disabled (as they were in Bitcoin Core-SegWit).

The only real questions here are:

1) why would the Core team disable this type of transaction? The answer is to force fees to increase which would push users onto their "2nd layer" solution products such as "Liquid"(R) or "Lightning"(R) Networks.

2) Why is anyone still using such a worthless cryptocurrency? That I don't know, Bitcoin Cash is Bitcoin now, Ethereum is Bitcoin 2.0 and already we have plenty of block space on literally thousands of other coins with no fees.

Re: Why Is It Taking 20 Minutes to Mine This Bitcoin Block?

#115

Post by branx » Tue, Feb 27, 2018, 5:24 PM UTC

sebbyBinx wrote: post #31

ballenf wrote: post #14

Does this mean that the second block from a random point in time is, on average, 20 minutes away? Anyone know what the longest wait time on a block in recent history was? Final question -- do large mining operations network their miners so that they don't overlap their hashes. I'm thinking the overhead in doing that would probably be counter-productive given the massive problem space. But, if they were networked that…

There was a 1.5 hour gap after this block: https://blockchain.info/block-height/152217

I'm confused...it says the Block Reward was 50BTC but I thought that miners are only supposed to get 1 per block?

Re: Why Is It Taking 20 Minutes to Mine This Bitcoin Block?

#116

Post by jron » Tue, Feb 27, 2018, 7:51 PM UTC

dlubarov wrote: post #44

oska wrote: post #35

Earlier quoted context omitted.

Most simple criticisms of why Bitcoin does things the way it does and then suggestions for simple ‘improvements’ such as yours (5 minute interval) tend to be naive and wrong. The 10 minute interval for Bitcoin transactions was chosen as the best tradeoff to balance pros and cons for making it shorter or longer. Stackexchange has a good discussion on the topic: https://bitcoin.stackexchange.com/questions/1863/why-was-…

10 minutes was Satoshi's very rough guess at what a reasonable compromise might be. He didn't have any empirical data and probably didn't give it much thought. Since then we have some real data about propagation times, e.g. [1], and most other blockchains have chosen much faster block times, like ~12s for Ethereum. [1] http://www.tik.ee.ethz.ch/file/49318d3f56c1d525aabf7fda78b23...

Ethereum's security model is totally different: https://eprint.iacr.org/2016/555.pdf If you look at bitcoin based POW intervals, 10 minutes is very close to optimal: https://eprint.iacr.org/2015/1019.pdf

Re: Why Is It Taking 20 Minutes to Mine This Bitcoin Block?

#117

Post by jlhawn » Tue, Feb 27, 2018, 8:00 PM UTC

jlhawn wrote: post #43

I wrote a quick little program to sort of prove this to myself: https://play.golang.org/p/fITZrZgzTT7 While the average difference in time between one record and the next is 10, the weighted average over the entire duration is 20.

I updated it with some comments explaining what's going on: https://play.golang.org/p/xEnlcwBX4CN

Re: Why Is It Taking 20 Minutes to Mine This Bitcoin Block?

#118

Post by photojosh » Tue, Feb 27, 2018, 9:38 PM UTC

travisjungroth wrote: post #12

alschwalm wrote: post #5

The article on the "hitchhiker's paradox" that this links to made this much more clear to me (as well as being shorter): https://the8layers.com/2016/10/30/how-long-will-you-wait-hit...

This reminds me of headwinds in airplanes. You might think that on average, wind cancels out. Sometimes you have a tailwind, sometimes you have a headwind and over time it will all average out. This is not the case. On average, wind reduces your groundspeed. The short of it is you spend more time in a headwind, so you spend more time experiencing the bad than good. There's also the fact that even a direct crosswind s…

Same with riding a bike in hilly terrain... you spend an hour climbing a hill, only to descend back down the other side in 10 minutes.

Re: Why Is It Taking 20 Minutes to Mine This Bitcoin Block?

#119

Post by dlubarov » Tue, Feb 27, 2018, 10:17 PM UTC

jron wrote: post #116

dlubarov wrote: post #44

Earlier quoted context omitted.

10 minutes was Satoshi's very rough guess at what a reasonable compromise might be. He didn't have any empirical data and probably didn't give it much thought. Since then we have some real data about propagation times, e.g. [1], and most other blockchains have chosen much faster block times, like ~12s for Ethereum. [1] http://www.tik.ee.ethz.ch/file/49318d3f56c1d525aabf7fda78b23...

Ethereum's security model is totally different: https://eprint.iacr.org/2016/555.pdf If you look at bitcoin based POW intervals, 10 minutes is very close to optimal: https://eprint.iacr.org/2015/1019.pdf

According to figure 2 in your second link, a blockchain with 1.5 rounds per block (or one block every ~19 seconds, based on their round length estimate) can withstand at least 40% hash power attacks. That seems like a reasonable tradeoff to me.

If you think 40% is not good enough, okay, let's target 48%. That's still just ~6.5 rounds per block (~82 seconds per block). Bitcoin's parameter of ~47 rounds per block is clearly overkill; the authors' graphs don't even go that far out (see figure 3).

Interestingly, the first paper you linked mentions that although Ethereum was intended to use single-level GHOST scoring, uncle blocks aren't actually counted toward chain difficulty, so it really has the same security model as Bitcoin. This was also confirmed by an Ethereum dev [1].

[1] https://ethereum.stackexchange.com/a/13750

Re: Why Is It Taking 20 Minutes to Mine This Bitcoin Block?

#120

Post by tvladeck » Tue, Feb 27, 2018, 10:31 PM UTC

modeless wrote: post #98

tvladeck wrote: post #62

> Correct, that is exactly what I am saying. If you pick a random point in time, you expect 20 minutes between the previous block and the next block on average. I thought this sounded funny, and I did a little simulation to see if it was correct. Given his assumptions (poisson with lambda 10), you do not get that answer. I got right around 10, which is what I would expect. https://gist.github.com/tvladeck/e7a164dfe70…

You are using rpois as if it returned the time between blocks, but that's wrong. It returns a count of blocks mined in a certain amount of time. Here is a formula to calculate your cumulative_times array correctly for a 10,000 minute period (which is expected to generate 1,000 blocks but may vary of course): minutes = 10000 cumulative_times See https://en.wikipedia.org/wiki/Poisson_point_process#Simulati... With corr…

ahhh you're right